The numbers won’t go up, or they do go up and then drop back down right away?

The numbers should always be able to go up or down. In order to enter the set mode the buttons on the G2 Control Panel must be held for 3 seconds. It will then enter set mode until no additional adjustments are made to ionization setting. If the numbers will not raise or lower, and you are holding the button down for 3 seconds, then replace the control panel (item #95017). If the numbers will raise, but go back down again, make sure there is sufficient flow going across the probe. Check the probe for excessive scale build-up or debris. Scale build-up can be caused by insufficient water flow. The scale build-up will decrease the amount of ions being released into the water affecting the ability to raise or lower the panel. Check the probe for build-up and brush or scrape the bars. If you notice this happening frequently, try moving the probe to a location with higher water flow. Water chemistry will also play a role in this. Make sure your alkalinity is at 100-250ppm. Adding a small amount of salt can help raise the conductivity in the water allowing the control panel to raise higher, BUT this will also “super-charge” the probe causing it to exhaust quicker. The conductivity can be easily raised by adding Aquascape's Pond Salt per the dosing recommendations on the bottle.